Donald Trump had to squeeze through a hole in a fence to speak at the California Republican Convention on Friday. He said it felt like "crossing the border." Meanwhile, his supporters swaggered into the Hyatt Regency San Francisco Airport banquet hall as if they owned the place. Maybe they know something I don't, I shuddered.

Before Trump's talk, I spoke with many party workhorses -- the folks who have sustained the GOP in challenging times. They tended to be skeptical of Trump's credentials as a Republican and of his chance of winning in November. Trump fans, for their part, were in their glory. Their faces glowed with the flush of expected triumph.

"He's honest," Bill Gilbert of Woodside, California, told me. "He talks straight." It was his first GOP convention. Kathy Mosta of Pleasant Hill, also at her first convention, said, "I love him because he mean what he say." Her syntax is not perfect because she is Persian. She's also Muslim, she told me, and she supports Trump's call to ban Muslims from entering the country. Another Trump supporter, Luisa Aranda, was wearing a T-shirt that said, "Latinos for the Wall." Methinks the supporters who defy stereotypes charged up others who could tell themselves: If Latinos and Muslims and women can stand behind Trump, the juggernaut is unstoppable.

They love Trump because he wins; he promises to lead the Republican Party back into the promised land of victory. "We're going to start winning again," Trump told the crowd. It's "a tougher road for a Republican than it is for a Democrat." Usually, he can tell whether a candidate will win a state just by looking at the map, he said, but he'll break the map. "We bring New York into play," Trump proclaimed. "Republicans will never beat Hillary in Florida. I will. I'll win in Pennsylvania." Given the way that Trump trounced Sen. Ted Cruz of Texas and Ohio Gov. John Kasich in those states, Trump's claims did not seem outrageous.

Except, as GOP wise man Rob Stutzman noted afterward, Hillary Clinton won more votes than Trump in all three states. She won more than a million votes in New York -- almost double Trump's 524,932 take. She won 20,000 more votes than Trump in both Florida and Pennsylvania.

Though the latest Rasmussen Reports poll found Clinton and Trump even -- with 38 percent of the vote each -- all other major polls show Clinton beating Trump. The Republican who beats Clinton is Kasich.

Trump got lots of laughs when he joked about Kasich's eating during press availabilities. That's the sort of hubris one sees before the fall.

Stutzman has partnered with GOP consultants Ray McNally and Richard Temple in an effort to deny Trump the 1,237 delegates it takes to win the nomination. As Temple told me, the California primary involves 172 delegates. Ten delegates go to the statewide winner. Three are superdelegates to the Republican National Committee. The vast majority of them are awarded winner-take-all to the top vote-getter in each of the state's 53 congressional districts. As Temple noted, it's like having 53 little state primaries.

The RealClearPolitics polling average gives Trump 46 percent of the vote in California, with 28 percent for Cruz and 18 percent for Kasich. But as Temple noted, a candidate can win the most votes statewide without winning a corresponding number of delegates. A moderate candidate, for example, can win as many delegates in a Bay Area district, where about 4,800 households are likely to vote Republican, as another candidate gets for winning a district with four times as many GOP voters. Temple wants to strike a blow for party stalwarts who have turned out in hard times and really don't want to see Trump on the ticket in November.

Quoth Temple: "California is the firewall to stop" Trump -- or hand him the nomination.